* Re: [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies
@ 2012-10-26 6:16 MyungJoo Ham
2012-10-31 0:45 ` Rafael J. Wysocki
0 siblings, 1 reply; 4+ messages in thread
From: MyungJoo Ham @ 2012-10-26 6:16 UTC (permalink / raw)
To: Nishanth Menon, linux-pm
Cc: Rajagopal Venkat, 박경민,
Rafael J. Wysocki, Kevin Hilman, linux-kernel
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> devfreq governors such as ondemand are controlled by a min and
> max frequency, while governors like userspace governor allow us
> to set a specific frequency.
> However, for the same specific device, depending on the SoC, the
> available frequencies can vary.
>
> So expose the available frequencies as a snapshot over sysfs to
> allow informed decisions.
>
> This was inspired by cpufreq framework's equivalent for similar
> usage sysfs node: scaling_available_frequencies.
>
> Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
> Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> Cc: Kevin Hilman <khilman@ti.com>
> Cc: linux-pm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
>
> Signed-off-by: Nishanth Menon <nm@ti.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies
2012-10-26 6:16 [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies MyungJoo Ham
@ 2012-10-31 0:45 ` Rafael J. Wysocki
0 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2012-10-31 0:45 UTC (permalink / raw)
To: myungjoo.ham
Cc: Nishanth Menon, linux-pm, Rajagopal Venkat,
박경민,
Kevin Hilman, linux-kernel
On Friday, October 26, 2012 06:16:36 AM MyungJoo Ham wrote:
> > devfreq governors such as ondemand are controlled by a min and
> > max frequency, while governors like userspace governor allow us
> > to set a specific frequency.
> > However, for the same specific device, depending on the SoC, the
> > available frequencies can vary.
> >
> > So expose the available frequencies as a snapshot over sysfs to
> > allow informed decisions.
> >
> > This was inspired by cpufreq framework's equivalent for similar
> > usage sysfs node: scaling_available_frequencies.
> >
> > Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
> > Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
> > Cc: Kyungmin Park <kyungmin.park@samsung.com>
> > Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> > Cc: Kevin Hilman <khilman@ti.com>
> > Cc: linux-pm@vger.kernel.org
> > Cc: linux-kernel@vger.kernel.org
> >
> > Signed-off-by: Nishanth Menon <nm@ti.com>
>
> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Are you going to handle this patch?
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies
2012-10-31 2:11 MyungJoo Ham
@ 2012-10-31 9:15 ` Rafael J. Wysocki
0 siblings, 0 replies; 4+ messages in thread
From: Rafael J. Wysocki @ 2012-10-31 9:15 UTC (permalink / raw)
To: myungjoo.ham
Cc: Nishanth Menon, linux-pm, Rajagopal Venkat,
박경민,
Kevin Hilman, linux-kernel
On Wednesday, October 31, 2012 02:11:06 AM MyungJoo Ham wrote:
> > On Friday, October 26, 2012 06:16:36 AM MyungJoo Ham wrote:
> > > > devfreq governors such as ondemand are controlled by a min and
> > > > max frequency, while governors like userspace governor allow us
> > > > to set a specific frequency.
> > > > However, for the same specific device, depending on the SoC, the
> > > > available frequencies can vary.
> > > >
> > > > So expose the available frequencies as a snapshot over sysfs to
> > > > allow informed decisions.
> > > >
> > > > This was inspired by cpufreq framework's equivalent for similar
> > > > usage sysfs node: scaling_available_frequencies.
> > > >
> > > > Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
> > > > Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
> > > > Cc: Kyungmin Park <kyungmin.park@samsung.com>
> > > > Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
> > > > Cc: Kevin Hilman <khilman@ti.com>
> > > > Cc: linux-pm@vger.kernel.org
> > > > Cc: linux-kernel@vger.kernel.org
> > > >
> > > > Signed-off-by: Nishanth Menon <nm@ti.com>
> > >
> > > Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
> >
> > Are you going to handle this patch?
>
> Yes, I've just setup the git repository this week
> and I'm willing to handle this one.
>
> It is applied at
> http://git.kernel.org/?p=linux/kernel/git/mzx/devfreq.git;a=shortlog;h=refs/heads/for-rafael
OK
Please let me know when you want me to pull from your tree.
Please also note that the release of v3.7-rc6 is the deadline for non-bugfix
changes targeted at v3.8. :-)
Thanks,
Rafael
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies
[not found] <[for-next PATCH] PM / devfreq: Add sysfs node to expose available frequencies>
@ 2012-10-26 0:48 ` Nishanth Menon
0 siblings, 0 replies; 4+ messages in thread
From: Nishanth Menon @ 2012-10-26 0:48 UTC (permalink / raw)
To: linux-pm
Cc: Nishanth Menon, Rajagopal Venkat, MyungJoo Ham, Kyungmin Park,
Rafael J. Wysocki, Kevin Hilman, linux-kernel
devfreq governors such as ondemand are controlled by a min and
max frequency, while governors like userspace governor allow us
to set a specific frequency.
However, for the same specific device, depending on the SoC, the
available frequencies can vary.
So expose the available frequencies as a snapshot over sysfs to
allow informed decisions.
This was inspired by cpufreq framework's equivalent for similar
usage sysfs node: scaling_available_frequencies.
Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kevin Hilman <khilman@ti.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Nishanth Menon <nm@ti.com>
---
Applies on top of Rafael's linux-next branch:
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git
linux-next b960e9a Merge branch 'pm-sleep-next' into linux-next
Example output from Beagleboard XM (3730) using a dummy test driver
http://pastebin.pandaboard.org/index.php/view/85100576 :
/sys/devices/platform/iva.0/devfreq/iva.0 # cat available_frequencies
260000000 520000000 660000000
/sys/devices/platform/iva.0/devfreq/iva.0 # cat available_frequencies|tr ' ' '-'
260000000-520000000-660000000
V2 :
- review comment update from v1
- protected the sysfs from buffer overflow - just in case..
V1: https://patchwork.kernel.org/patch/1648001/
Documentation/ABI/testing/sysfs-class-devfreq | 9 +++++++
drivers/devfreq/devfreq.c | 32 +++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index e6cf08e..e672ccb 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -51,3 +51,12 @@ Description:
The /sys/class/devfreq/.../userspace/set_freq shows and
sets the requested frequency for the devfreq object if
userspace governor is in effect.
+
+What: /sys/class/devfreq/.../available_frequencies
+Date: October 2012
+Contact: Nishanth Menon <nm@ti.com>
+Description:
+ The /sys/class/devfreq/.../available_frequencies shows
+ the available frequencies of the corresponding devfreq object.
+ This is a snapshot of available frequencies and not limited
+ by the min/max frequency restrictions.
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d02ee7e..104018e 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -571,9 +571,41 @@ static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
}
+static ssize_t show_available_freqs(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(d);
+ struct device *dev = df->dev.parent;
+ struct opp *opp;
+ ssize_t count = 0;
+ unsigned long freq = 0;
+
+ rcu_read_lock();
+ do {
+ opp = opp_find_freq_ceil(dev, &freq);
+ if (IS_ERR(opp))
+ break;
+
+ count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+ "%lu ", freq);
+ freq++;
+ } while (1);
+ rcu_read_unlock();
+
+ /* Truncate the trailing space */
+ if (count)
+ count--;
+
+ count += sprintf(&buf[count], "\n");
+
+ return count;
+}
+
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO, show_governor, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
+ __ATTR(available_frequencies, S_IRUGO, show_available_freqs, NULL),
__ATTR(target_freq, S_IRUGO, show_target_freq, NULL),
__ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval,
store_polling_interval),
--
1.7.9.5
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2012-10-26 6:16 [for-next PATCH V2] PM / devfreq: Add sysfs node to expose available frequencies MyungJoo Ham
2012-10-31 0:45 ` Rafael J. Wysocki
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2012-10-31 2:11 MyungJoo Ham
2012-10-31 9:15 ` Rafael J. Wysocki
[not found] <[for-next PATCH] PM / devfreq: Add sysfs node to expose available frequencies>
2012-10-26 0:48 ` Nishanth Menon
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